APES 1.8 - Primary Productivity

units

kcal/m2/year

energy/area/time

how does high primary productivity affect an ecosystem?

high primary productivity leads to high plant growth, which leads to lots of food and shelter for animals

how does high primary productivity relate to biodiversity in an ecosystem?

ecosystems with high primary productivity are usually more diverse than ecosystems with low primary productivity

primary productivity

the rate that solar energy is converted into organic compounds via photosynthesis over a unit of time

what is primary productivity also known as?

the rate of photosynthesis of all producers in an area over a given period of time

how can primary productivity be thought of in relation to photosynthesis and plant growth?

since photosynthesis leads to growth, primary productivity can be thought of as the amount of plant growth in an area over a given period of time

calculation primary productivity

NPP = GPP - RL

net primary productivity (NPP)

amount of energy (biomass) leftover for consumers after plants have used some for cellular respiration

respiration loss (RL)

plants use up some of the energy they generate via photosynthesis by undergoing cellular respiration

gross primary productivity (GPP)

total amount of sun energy (light) that plants capture and convert to energy (glucose) through photosynthesis

ecological efficiency

the portion of incoming solar energy that is captured by plants and converted into biomass (NPP or food available for consumers)

what percent of incoming sunlight is captured and converted into GPP via photosynthesis?

1%

how much of the 1% is converted into biomass/plant growth (NPP)?

40% or 0.4% total

trends in productivity

the more productive a biome is, the wider diversity of animal life it can support (higher biodiversity)

factors that lead to high NPP

water availability, higher temperatures, and nutrient availability

most productive aquatic biomes

coral reefs and salt marshes

least productive aquatic biomes

open ocean

most productive terrestrial biomes

swamps, marshes, and tropical rainforests

least productive terrestrial biomes

tundra and desert scrub